andy_vs

Couple of things. The muscle simulation is a good start but needs some finessing. Do you have your solver scale set correctly? It should be about half the height of your creature if your creature was the same size as a moose or something.

If it's set correctly, then the muscle materials might be too stiff. You shouldn't have to deviate from the defaults very much if your solver scale is set correctly.

What about muscle fibers, do you have them auto firing?

I've done a draw over of a couple of poses:

The brachiocephalicus looks like it needs to pull straighter when he (she?) reaches forward. This is causing a pinch which gets passed down to the skin.

The brachioradialis doesn't feel like it's contracting when the leg bends.

For some reason , generally, the muscles appear kind of stiff, or damped. It might be that they're over constrained. Are you using very stiff sliding attachments / fixed attachments between muscles? How many substeps are you running, and are you using any damping generally?

As for the fascia, there's definitely some cool sliding going on. You see it when you switch to the textured version. I'm wondering if you are using rest scale and pressure together? It seems like you're losing some of that nice detail that's sculpted into the fascia in your still image that you posted.

Without that detail, there won't be any details passed down to the fat / skin. There's probably an opportunity getting missed with getting some of that rippling muscle getting passed to the skin 🙂

While the wrinkling all over the skin looks interesting it might be better for focus the wrinkling that typically occur in areas that undergo a lot of compression like where the legs connect to the ribcage and the knees / elbows.

Thanks for posting your stuff! Hope some of this is useful 🙂

Stathis

andy_vs
Hi Andy,
thanks for your reply.
My solver has default scale, the creature is though very tall almost 3 and a half meters.
This was the reason that i stiffen the muscle materials with values 4-8 to 10>5.
When i was using the default values the muscles were having a weird gelo effect.
Muscle fibers are autofiring yes and the only thing i have adjust is the pos sensitivity set to 2.
For constraing, i have fixed constrains muscles to bones something like 10>9 and between them few sliding attachments with low values.
I haven't use any damp.
Susbsteps for muscle sim were 8.

For the fascia yes i used both rest scale and pressure with animated envelopes from 1 to 5 frame just like your tutorial.
I was trying to retain the details but i couldn't. Rest scale is set to 0.9 and i was raising pressure to retain the valleys and now its 4000 but still..
It also has two materials with same rest values, but for the first one the pressure is set to one and for the other i have paint the areas black for feet and tail.
Substeps for fascia sim were 10 with collision point 0.01(lower values crash maya)
Thanks

andy_vs

Hey, okay thanks for the info.

My suggestion for you is to set all the materials back to default and scale the solver up a bit. I've generally found it helpful to assume that your characters are about the same height as a human, and then experiment with damping/density per muscle to give the effect that the creature is larger.

If you do those things, the muscles may still feel 'droopy' under gravity. To tighten them back up, create zFibers on all your tissues and then add a little bit of excitation that's on all the time, something like 0.2.

Don't forget to set your muscle fibers back to default values too (if you already have fibers in your scene)

You can still have your line-of-action still firing the muscles on top of the constant 0.2 excitation.

wow! 4000 pressure and still no valleys? I've never seen pressure that high, good to know it's stable at least. I have to say that's pretty surprising. If you turn rest scale back to 1, are you seeing any pressure at all? Maybe that second material on the fascia is taking precedence which doesn't have a high pressure value?

Substeps and collision point spacing sound like good choices

Stathis

andy_vs
Hi Andy great i will try your suggestions for the muscles and i will let you know.
Although i tried to reduce the materials to something like 10>4 and it seems to be little better not so damp, i will post both versions.
For the fascia i had two materials with these settings:
1) rest scale 0.9
Pressure: 1
And painted all black with white feet and tail.
2) rest scale: 0.9
Pressure: 4000
And painted all white with black feet and tail.
For both materials of fascia the other settings were exactly the same.
1000
100
0.2
The exp values were default.
I will try to set rest scale back to 1 and i will let you know
Again thanks for your help

andy_vs

Hey,

Okay well something isn't right because if you have only two materials you can only paint weights on the top one. Ziva doesn't allow you to paint black on the lowest material in the stack.

Can you try deleting the top material layer (the one that appears first in the channel box, when you have the fascia selected) and double checking that all the vertices are painted white for the remaining layer.

Set the pressure high for the remaining layer and see if it's working?

Stathis

andy_vs
Hi Andy,
here is my latest muscles sim after your suggestions (solver scale set to 130, fibers excitation set to 0.2 and i adjust the density of the muscles from 106 to 306, pos sensitivity is set to 1)

For the fascia yes you were right, the first material was white, the second one had black feet and tail.
I tried again with this muscle sim ftom scratch with one material only.
Rest scale is set to 1 (now the valleys are retained) and for the pressure i tried several values from 1 to 100,1000
but after some frames fascia was exploding. Solver values were the same as before. I tried default values for the cloth but still..
Thanks

andy_vs

Okay, some more feedback for you.
Definitely getting a better shape for the brachiocephalicus.

Not seeing a meaningful change to the brachioradialis yet.
The volumes on the back leg still feel like they could be deforming better -- the whole muscle mass moves as one, rather than getting any individual play between muscles (sliding on each other, separating a little, etc)
Your muscle density is still pretty light at 306. Default is 1060.
Don't forget there is also the inertial damping attribute on the zTissue node that can negate some of the world space inertia going through your muscles, if you find they've got too much secondary motion.

I think you could double or even triple your pos sensitivity to 2 or 3, just to amplify the effect. See how you go.

As for the fascia pressure at 0.92 and pressure between 40 and 80 seemed to work for me. If the fascia is exploding it's usually because there are self intersections on the objects it's colliding with. This will cause our collision mechanism to do the wrong thing because the point-in-volume test won't properly against objects that have self-intersections.

You can run this loop on any frame to see if you have self-intersections:

Stathis

andy_vs
Hi Andy,
thanks for your reply.
I have some questions about muscle density. I thought that i have to reduce from default size which is 1060 in order to avoid the droopy effect. My values right now is something like between 80-306, larger values than these are making the muscles look like gelo. Am i right?
I have set my fibers to 0.2 constantly and now pos sens is 3.
For the brachioradialis (which has a different name in my scene) its seems that there is an error.
Ionnie had post me this and suggest me to paint the map again.

andy_vs

What I'm still not seeing that I'd love to see is nice "local" motion happening on larger muscle groups. They are moving but kind of appear to be hinging at the ends, rather than compressing/stretching/locally jiggling. By "local motion" I mean some parts of the muscle moving at different rates to other parts. I think this is what is making the character feel stiff, and not as organic or fleshy as it could be.

You mentioned that you increased the solver scale, and loosened up the attachments. Did you experiment with restoring the densities and Young's modulus to the original values?

Other stuff:
- I would say the deltoids appear to be separating a lot / not compressing (or stretching)
- The rectusfemoris and surrounding muscles appear to be buckling quite a lot, suggesting to me that the firing isn't quite working.

Once again, great to see your progress and apologies if I'm sounding extra critical, I just think we can get to a really great place with this character as the source material is so good, and you've done a lot of great work with the muscle/skeleton model etc.

Talk soon!
Andy

Stathis

andy_vs
Hi Andy thank you very much for your time and feedback.
I have restored all material properties to default settings.
I set solver scale to 380 in order to avoid the generall droopines.Any lower value than 380 make the myscles very droopy.
I will check again for these muscles that you point for firing.
Do you think raising pos sens for these specific curves will resolve the issue or i have to check something else?
Thanks again

Stathis

Here is another muscle sim.
For this one i lower the scale of solver to 330 and also lower the fibers excitation in some muscles.
Also i raised to 6 pos sens and lower more the stifness of sliding att and raised a bit some fixed att to the bone.